The invention relates to wireless communication systems and more particularly to a system and method for redirecting data messages.
A wireless data server extends e-mail messaging to subscribers of a wireless system. The conventional wireless data server typically supports message notification and delivery. Although the wireless data server itself may support message redirection, mobile stations in the wireless system must be appropriately equipped to handle such message redirection. Message redirection refers to a procedure in which the wireless data server directs a data message addressed to a mobile station to another electronic destination other than the mobile station.
For GSM (Global System for Mobile Communications) mobile stations and infrastructure, message redirection is readily implemented by using the short-messaging service (SMS) feature. Manufacturers typically offer SMS as a standard or optional feature. GSM supports SMS by allocating channels, or portions thereof, for message data on an as-needed basis. Many GSM systems support both downlink and uplink transmission of SMS messages containing up to 160 alphanumeric characters. The SMS messages may be displayed on a GSM mobile station and stored on a subscriber identity module (SIM) for subsequent reference. The subscriber identity module is removable card that provides user identification and data storage for a GSM mobile station.
However, while GSM readily supports two-way SMS, most TDMA (time-division multiple access) and CDMA (code-division multiple access) systems merely support one-way SMS. In particular, many TDMA and CDMA system only support mobile-terminated SMS in which the mobile station is unable to send message redirection data to the wireless data server. Because many wireless service providers in the U.S. have embraced the TDMA/CDMA systems to a larger extent than GSM, a need exists for making message redirection compatible with a data protocol such as one-way SMS.
In accordance with the present invention, a message redirection system (or method) uses a data protocol detector for detecting an alert message of a particular data protocol received by the mobile station. A user-interface manager displays user-interactive prompts in response to a detected alert message. The user-interface manager accepts user input for redirecting a data message to a communications network element. The alert message represents notification of the existence of a data message which is addressed to the mobile station. An encoder encodes the user input as a modulating signal compatible with a communications channel.
At the mobile station, the alert message may be received as a one-way short messaging service (SMS) message, or another suitable data protocol, that is detectable by the detector. The subscriber is able to respond to the one-way SMS message, or another suitable data protocol, by entering user input which is then encoded. In one embodiment of the invention, the encoder encodes the user input into a tone signal or another signal having a modulation frequency range such that the encoded user input may be transmitted from the mobile station as if it were an ordinary voice-channel transmission. In another embodiment, the encoder provides a modulating signal suitable for transmission over a control channel or an access channel without the need to setup a voice-channel call. The message redirection system is well-suited for implementation as a software-configurable or software-upgradable feature set.